Feeder having an improved conveyor device for mail items

ABSTRACT

In a feeder of a mail handling machine, a conveyor device is provided that includes a plurality of a drive members controlled by a suitable drive mechanism and designed to pass through a mail item receiver bed of said feeder, and each of said drive members is constituted by a cylindrical wheel provided with a set of straight teeth formed by a plurality of teeth between which there are interposed a plurality of independent small rollers having axes perpendicular to the axis of the wheel.

TECHNICAL FIELD

The present invention relates exclusively to the field of mail handling, and it relates more particularly to a mail item feed module of a mail handling machine, which module has an improved mail item conveyor device.

PRIOR ART

The postal specifications that govern printing of postal imprints are very precise and define, in particular, the position of the postal imprint relative to the top edge of the envelope. Achieving that position depends on the envelope being jogged into alignment. Since the envelope is conveyed parallel to a referencing wall (or “jogging” wall), a jogging error or misalignment in the feed magazine (or feeder) gives rise to the same error or misalignment downstream in the selector device and then even further downstream on going under the print module. It is thus very important to monitor and automatically correct such jogging errors in the feeder so as to avoid it being necessary for the operator to re-jog each stack of envelopes on inserting it into said feeder.

Today, in order to solve that problem, it is known that the conveyor rollers of the feeder can be inclined so that, by conveying the envelopes on a slant, they are shifted towards the referencing wall while also being conveyed towards the selector device. Unfortunately, by exerting a large re-jogging force on the envelope, that configuration brakes said envelope and, when said envelope is a fine envelope, can even damage it. In addition, the force exerted depends on the position of each conveyor roller relative to the selector device.

The Applicant has also proposed supplementing the conveyor rollers disposed parallel to the referencing wall with perpendicular re-jogging rollers that operate with a phase advance relative to said conveyor rollers.

However, even though the envelopes tend to be braked to a lesser extent than with the above configuration, the braking tendency nevertheless persists because of the action of said re-jogging rollers, and the greater the height and/or the weight of the stack of envelopes, the greater the extent to which the envelopes tend to be braked.

OBJECT AND DEFINITION OF THE INVENTION

An object of the present invention is thus to mitigate the above-mentioned drawbacks with a mail item feed device that has specific drive members making it possible to monitor and to correct the jogging of the mail items. Another object of the invention is to propose a device whose performance is independent of the weight and/or of the height of the stack of envelopes disposed on the feeder.

These objects are achieved with a mail item feeder for feeding mail items into a mail handling machine, said mail item feeder including a plurality of a drive members controlled by a suitable drive mechanism and designed to pass through a mail item receiver bed of said feeder, wherein each of said drive members is constituted by a cylindrical wheel provided with a set of straight teeth formed by a plurality of teeth between which there are interposed a plurality of independent small rollers having axes perpendicular to the axis of the wheel.

Thus, by having this specific structure, the drive members perform dual functions of conveying and of jogging, the coefficient of friction due to the re-jogging rollers is removed and the jogging can be performed without being detrimental to the mail items being conveyed.

Advantageously, said small rollers are mounted to be free to rotate about axes of rotation disposed in a plane that is perpendicular to the axis of rotation of said cylindrical wheel, each axis extending between the facing sides of two adjacent teeth.

Preferably, said axes of rotation of the small rollers are distributed around the sides of a regular polygon and are positioned at a determined distance from said axis of rotation of the wheel, and each of said small rollers has an outer peripheral surface that projects by approximately in the range 0.5 millimeters (mm) to 1 mm relative to tops of the teeth.

Said cylindrical wheel may be made of a standard low-cost material of the polyoxymethylene type, and said small roller may be made of silicone.

Advantageously, the device of the invention has at least six small rollers spaced apart uniformly at 600 intervals.

BRIEF DESCRIPTION OF THE DRAWING

The invention can be better understood on reading the following detailed description accompanied by illustrative and non-limiting examples given in the following figures, in which:

FIG. 1 is a perspective view of a feed device for a mail handling machine, which feed device incorporates an improved conveyor device of the invention;

FIG. 2 is a perspective view of one of the drive members of the conveyor device of FIG. 1; and

FIGS. 2A and 2B are section views on two perpendicular planes of the drive member of FIG. 2.

DETAILED DESCRIPTION OF EMBODIMENTS

A feed device (or feeder) for feeding mail items into a mail handling machine and that incorporates an improved conveyor device of the invention is shown in FIG. 1. This feeder 10 includes, in conventional manner, a mail item receiver bed 12 on which the mail items to be printed are placed in a compact stack that can be uniform or non-uniform (depending on whether or not the mail items are of the same size). Said mail items are conveyed to a selector device 14 by a conveyor device conventionally formed by a plurality of drive members such as the conveyor rollers 16 passing through the mail item receiver bed and controlled by a suitable drive mechanism 18.

In accordance with the invention, said rollers 16 of the conveyor device are disposed in line in a plurality of rows extending parallel to the referencing wall 20 of the feeder and, as shown more particularly in FIGS. 2, 2A, and 2B, each of the rollers is constituted by a cylindrical wheel provided with a set of straight teeth made up of a plurality of teeth 22 between which there are interposed a plurality of small rollers 24 having axes of rotation perpendicular to the axis of the wheel. More precisely, the small rollers are mounted to be free to rotate about axes of rotation 26 disposed in a plane that is perpendicular to the axis of rotation of the wheel, each axis extending between the facing sides 22A, 22B of two adjacent teeth. The axes of rotation of the small rollers are distributed around the sides of a regular polygon and are positioned at a determined distance from the axis of rotation of the wheel so that the outer peripheral surface of the small roller projects by approximately in the range 0.5 mm to 1 mm relative to the tops 22C of the teeth, and naturally does not come into contact with the bottom 22D of the gap between the teeth while said small roller is rotating. In the example shown, each roller has eight teeth and thus eight small rollers interposed between respective pairs of said teeth. Naturally, this number is in no way limiting and depends essentially on the diameter of the cylindrical wheel. Thus, a wheel with six small rollers spaced apart uniformly at 60° intervals is quite possible, as is a wheel having a greater number of small rollers. It should be noted that, with a configuration having a greater number of small rollers, the higher the number of small rollers, the closer the curve going through the outer peripheral surfaces of the small rollers comes to forming an exactly circular shape.

These small rollers are made of a material that is chosen as a function of the technical specifications (abrasion, friction, elasticity, and hardness) expected for driving, i.e. with a coefficient of friction that is sufficiently large to enable the mail items to be driven towards the selector device. Such a material is, for example, silicone, natural rubber, polyurethane, or indeed ethylene propylene diene monomer (EPDM). However, since the wheel is involved very little in the processes of conveying and of jogging, its material is chosen to be low-cost, e.g. a material based on polyoxymethylene. 

1. A mail item feeder for feeding mail items into a mail handling machine, said mail item feeder including a plurality of a drive members controlled by a suitable drive mechanism and designed to pass through a mail item receiver bed of said feeder, wherein each of said drive members is constituted by a cylindrical wheel provided with a set of straight teeth formed by a plurality of teeth between which there are interposed a plurality of independent small rollers having axes perpendicular to the axis of the wheel.
 2. A mail item feeder according to claim 1, wherein said small rollers are mounted to be free to rotate about axes of rotation disposed in a plane that is perpendicular to the axis of rotation of said cylindrical wheel, each axis extending between the facing sides of two adjacent teeth.
 3. A mail item feeder according to claim 2, wherein said axes of rotation of the small rollers are distributed around the sides of a regular polygon and are positioned at a determined distance from said axis of rotation of the wheel.
 4. A mail item feeder according to claim 3, wherein each of said small rollers has an outer peripheral surface that projects by approximately in the range 0.5 mm to 1 mm relative to tops of the teeth.
 5. A mail item feeder according to claim 1, wherein said cylindrical wheel is made of a standard low-cost material of the polyoxymethylene type.
 6. A mail item feeder according to claim 1, wherein said small roller is made of one of the following materials: silicone, polyurethane, natural rubber, ethylene propylene diene monomer.
 7. A mail item feeder according to claim 1, having at least six small-rollers spaced apart uniformly at 60° intervals. 